Method of assembling a multiplexer/demultiplexer apparatus to account for manufacturing variations in the thin-film optical filters

A method for assembling an optical multiplexer/demultiplexer apparatus, comprising the steps of

• furnishing a component set comprising
• a base
• an input collimator
• a first thin-film optical tilter and a second thin-film optical filter, and
• a first transmitted-light collimator and a second transmitted light collimator;
• orienting the thin-film optical filters by the steps of
• fixing said input collimator to the base
• first locating the first thin-film optical filter so that a first incident light beam from said input collimator is incident upon the first thin-film optical filter, thereafter
• first orienting the first thin-film optical filter to produce a first angle-of-incidence of the first incident light beam on the first thin-film optical filter so that a desired first-transmitted light beam is transmitted therethrough with a maximum intensity and a second incident light beam is reflected from the first thin-film optical filter, thereafter
• second locating the second thin-film optical filter so that the second incident light beam is incident upon the second thin-film optical tilter, and thereafter
• second orienting the second thin-film optical filter to produce a second angle-of-incidence of the second incident light beam on the second thin-film optical filter so that a desired second-transmitted light beam is transmitted therethrough with a maximum intensity and a third incident light beam is reflected from the second thin-film optical filter;
• and positioning the transmitted-light collimators by the steps of
• first positioning the first transmitted-light collimator to receive the first-transmitted light beam with minimal insertion loss, wherein the step of first positioning is performed independently of, but after, the step of first orienting, and
• second positioning the second transmitted-light collimator to receive the second-transmitted light beam with minimal insertion loss, wherein the step of second positioning is performed independently of, but after, the step of second orienting.